NZ197672A - Making caramel from lactose;lactose/acid solution hydrolysed at 125-178 grad - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number 1 97672 FORM S.9.

N L A LAND Fee: $00 »vO 1 *°1 r.j r=* rf vQ) a N.Z. PA < ENT OFFICE -5 JAN 1984 PATENTS ACT 195 3 Insert number of ProvisionaI Specification(s) (if any) and date(s) of fi ling; otherwise leave blank.

Number: 197672 Date: 1C January 1982 COMPLETE SPECIFICATION Insert TitLe of Invention.

Insert full name, full street address and nationality of (each) applicant.

METHOD OF MAKING A CARAMEL -Z/WE STEVEN MARK LONGDEN, a citizen of the United Kingdom, of 112 First View Avenue, Beachlands, Auckland, New Zealand and GRAEME THOMAS SHEPHERD, a New Zealand citizen of 14 Puhinui Road, Papatoetoe, Auckland, New Zealand hereby declare the invention for v/hich Z/we pray that a patent may be granted to pte/us and the method by which it is to be performed, to be particularly described in and by the following statement Indicate if following page is numbered '1(a)1 1 This invention relates to a method of making a caramel product.

Caramel is an amorphous brown colouring agent v/hich may be used to colour and flavour a range of foodstuffs such as, for example, meat pies, gravy and beer. Caramels may be measured for colour using a tintometer, and graded according to darkness or tintorial power on a scale established by the European Brewery Commission.

The decomposition of sugars to produce caramel is well-known, but prior art methods have typically used such sugars as glucose, sucrose, and starch ac their starting material. The method of the present invention however, uses lactose as the raw sugar ingredient. This is advantageous in Mew Zealand because lactose is readily and cheaply available as a by-product of our dairy industry. However lactose has not been used successfully to produce caramel hitherto, because the low solubility of lactose was assumed to prohibit hydrolysis of lactose without use of an expensive enzyme.

It is an object of the present invention to provide a method of making a caramel product using a starting material which is both cheap and plentiful on the local market and which 197672 does not have to be imported to New Zealand. It is a further object of the invention to provide a commercially viable method of converting lactose into a caramel which produces a caramel product which has colouring and flavouring characteristics which are acceptable to the food industry. It is also an object of this invention to provide a caramel that is relatively stable over a long period" of time, and in the presence of acids and alcohols, and is of relatively uniform colour.

In a first aspect the present invention consists in a method of making a caramel comprising the steps of: mixing ^0 lactose, with or without other sugars, to a combined amount of 70 to 90% of solids by weight with water acidified to a pH of 0.2 to 4.5 at an initial temperature of substantially 80°Cf applying pressure of 80 to l,OOOkPa and hydrolysing the lactose solution at a temperature between 125°C and 178°C to form a syrup, adjusting the solids content and pH of the syrup if necessary to 70 to 90% of solids by weight 15 with a pH of 0.2 to 4.5 by adding or removing water and by adding acid or alkali as required, then caramelising the syrup with either an aqueous solution of ammonia or a compound having at least one free amino group.

In a second aspect the present invention broadly consists in a caramel product when made by the method described above.

The above gives a broad outline of the present invention, a preferred form of which will now be described.

In the preferred method, a measured volume of water is heated in a pressure cooker. The water may be acidified by 1976*72 the addition of an acid until the pH is substantially between 0.2 and 4.5. One or a mixture of acids may be used. Preferred acids are acetic acid, phosphoric acid, citric acid, sulphuric acid, and hydrochloric acid. An advantage 5 of the method is that weak acids such as acetic, phosphoric and citric acid may be employed, which do not attack" the equipment being utilised.

A known weight of lactose is then added to the "solution", 10 which is actually a part suspension/part solution of lactose and water, of which between 7 0% and 90% by weight comprises solids. The solution is preferably agitated during the addi tion. . ^5 The solution is heated, under pressure for a further period of time. The lactose solution is hydrolysed by the acid treatment to form a syrupy product comprising glucose and galactose. The hydrolysis is carried out at a temperature between 125°C and 178°C, and at a pressure of between 80 kPa 20 and 1000 kPa. The time required for the hydrolysis will vary between one second and three hours according to the percentage of solids in the solution, the acidity of the solution, the acids used to effect the hydrolysis, and the temperature and pressure under which the hydrolysis is 25 undertaken. .• ,/ I i '/ / - "* I 197672 Preferably, impurities such as proteins and fats are substantially removed from the lactose prior to its addition to the acidified water. The impurities may be removed by filtering the lactose, dissolving and crystallising the lactose and treating the crystals using methods well known to those involved in handling dairy by-products containing lactose.

The resulting product is reacted with a known quantity of a caramelisation agent being an aqueous solution of ammonia. Preferably at least 50% of the ammonia comprises ammonium carbonate, anhydrous ammonia or aqueous ammonia, the balance comprising an ammonium salt. Preferably the amount of ammonia added is between 0.5% and 3.8% by weight of the dry solids in the product of the hydrolysis step. This range should produce a caramel with a tintorial power of approximately 20,000 to 40,000 EBC units. Prior to the reaction, the syrup should be substantially 70% to 90% solids by weight with a pH of substantially 0.2 to 4.5. If necessary, this may be achieved by the addition of an acid or alkali, or by evaporation or dilution with water.

The mixture is heated to a preferred range of between 100°C and 200°C depending upon the substances used, under a / J ■ / / f* 197672 pressure of between 0 and 1500 kPa for a further period.

During this heating period the contents of the cooker should preferably be agitated. Finally, the product is cooled to near room temperature and the pressure in the cooker 5 relieved. The pH may be adjusted by adding sodium hydroxide. The resulting caramel should be filtered prior to storage.

One of a mixture of chemical substances may be added to the 10 product prior to the second heating stage to control, for example, the pH, the rate of development of the tintorial power, and the stability of the finished product to, inter alia, acids, tannins, and colloidal substances. The chemical substances are preferably one or a mixture of the following: acetic acid, citric acid, hydrochloric acid, phosphoric acid, sulphuric acid; ammonia as aqueous ammonia, anhydrous ammonia, ammonium carbonate, or an ammonium salt, ammonium hydroxide, ammonium citrate, ammonium sulphate, ammonium sulphite, ammonium hydrogen sulphite; sodium 20 carbonate, sodium sulphite, sodium hydrogen sulphite, sodium metabisulphite, sulphur dioxide or urea.

Caramels may be classified as 'positive' or 'negative1. A positive caramel has a positively charged colloid. The — 25 above process will produce a positive caramel. A negative / "r' i , / 197672 caramel is generally formed if the sulphite ion is present.

The above method v/ill now be clarified with reference to the following examples.

Example 1 (single strength ammonium sulphite caramel) 1000 grams of water is acidified to pll 0.8 by adding hydrochloric acid. The acidified water is then heated and 10 maintained at substantially 80°C while 4000 grains of lactose is added. The suspension is heated to 155°C for one second at a pressure of approximately 480 kPa and may be cooled to room temperature. A syrup with a dissolved solids content of about 84.55 is produced.

This syrup is heated to 84 °C, and 8 3 8 grams of a caramelisation agent: consisting of sodium acid sulphite, ammonium sulphate, ammonium hydroxide and water in the ratio of 7:1:5:7 is added. The ratio of NaHSO^ to HH^ should be 20 between 3.3:1 to 7:1 and the ratio of HaHSO^ to (ITF^^SO^ should be between 4:1 and 7:1. The mixture is agitated for approximately 5 minutes, then the vessel is sealed. The mixture is then heated to 155°C at a pressure of approximately 480 kPa for 30 minutes. The pressure in the 25 vessel is then reduced to 300 kPa to vaporise impurities in 197672- the mixture which are drawn off. The temperature and pressure are kept stable and samples of the product are taken until a tintorial power of substantially between 20,000 and 24,000 EEC is obtained. The syrup is then cooled to substantially 60°C. The pH is then adjusted from its current level of substantially 2.7 to substantially 3.0 by adding sodium hydroxide. The resulting negatively charged caramel is filtered and stored.

Example 2 (ammonia caramel) RAW PREFERRED MATERIAL QUANTITY Water (may use mains, 637 ml distilled or deionised) Aqueous ammonia 539 ml 0.89 s.g.

Hydrochloric acid 2.8 ml 33 1/3 % w/v Lactose 2.95 kg y 197672 The general method described above was followed, the original aliquot of lactose being 1 kg, the first heating (under pressure) step being for 20 minutes, and the final heating (under pressure) step being for 60 minutes.

Various modifications may be made to the above method without departing from the scope of the invention. Some of these are noted below together with observations on the effect various reaction conditions may have on the quality of the caramel product.

The sugar-aqueous ammonia reaction may be replaced by a sugar-amino group reaction. The amino group may be provided by an amino acid, a protein or a peptide.

Various acids may be added to the reaction mixture to alter the pH, specific gravity and stability of the product. Examples of acids which may be used instead of, or as well as, hydrochloric acid, are phosphoric acid, sulphuric acid, sulphurous acid, acetic acid and citric acid. . < The acid, heat and pressure catalysed decomposition of lactose may be replaced by an enzymatic hydrolysis of lactose to form a product comprising glucose and galactose, using an enzyme or by cation exchange. t97672 The identity of the sugar used may be varied from lactose alone to a mixture of lactose and at least one other sugar, although it is anticipated that a satisfactory product will require the use of at least 10% lactose in the mixture. Sucrose, carbohydrate or starch hydrolysates may be mixed with the hydrolysis product prior to the second heating stage.

The use of too little water in the reaction mi::ture has been found to result in a very thick caramel, which is probably polymerised, whereas too much water causes a very thin caramel having a pale colour and promotes flocculation.

The use of too little lactose results in a light coloured caramel of low specific gravity and low viscosity, whereas too much lactose in the reaction mixture slows the rate of conversion of sugar to the caramel product.

The use of too much acid lowers the pH to an unacceptable value and results in an acid-tasting product. Insufficient acid reduces the flavour of the product and slows the rate of hydrolysis of the lactose. 197672 The use of too much aqueous ammonia gives a more stable product having a strong flavour and intense colour, but having a specific gravity v/hich is too low. Too little aqueous ammonia results in a product which is more viscous, 5 has a low pH and is less stable.

The reaction step in which aqueous ammonia is added to the reaction mixture should be carefully controlled. A compromise should be reached between rapid addition of the 10 aqueous ammonia which limits the depth of colour achieved in the product, and slow addition, which promotes volatilisation of the ammonia.

The method may be modified by eliminating the heating steps 15 (but retaining the pressure treatment), but the rate of caramelisation will be greatly reduced.

Elimination of the pressure treatment and retention of the heating step may cause serious instability in the caramel 20 product and promotes polymerisation reactions which are not desirable.

The method may be adapted for use in a continuous mode rather than a batch mode. 197672

Claims (8)

WHAT WE CLAIM IS:

1. A method of making a caramel comprising the steps of: mixing lactose, with or without other sugars, to a combined amount of 70 to 90% of solids by weight with water acidified to a pH of 0.2 to 4.5 at an initial temperature of substantially 80°C, applying pressure of 80 to l,OOOkPa and hydrolysing the lactose solution at a temperature between 125°C and 178°C to form a syrup, adjusting the solids content and pH of the syrup if necessary to 70 to 90% of solids by weight with a pH of 0.2 to 4.5 by adding or removing water and by adding acid or alkali as required, then caramelising the syrup with either an aqueous solution of ammonia or a compound having at least one free amino group.

2. A method as claimed in Claim 1, wherein the compound having at least one free amino group used in caramelising the syrup comprises an amino acid.

3. A method as claimed in Claim 1, wherein the compound having at least one free amino group used in caramelising the syrup comprises a protein.

4. A method as claimed in Claim 1, wherein the compound having at least one free amino group used in caramelising -12- 197672 the syrup comprises a peptide.

5. A method as claimed in any one of the preceding claims, wherein hydrolysates of sucrose, starch or carbohydrates are added to the syrup prior to caramelising the syrup.

6. A method of making a caramel as claimed in Claim 1 and substantially as herein described with reference to Example 1.

7. A method of making a caramel as claimed in Claim 1 and substantially as herein described with reference to Example 2.

8. A caramel product when made by method as claimed in any one of Claims 1 to 7. J. D. KARDiE & CO. ' Patent Attorneys for the Applicants). -13-